The present invention relates to a semiconductor device, for example to a technology effectively applicable to a semiconductor device used for a power supply circuit.
A DC/DC converter widely used as a power supply circuit includes a high side switch, a low side switch, drivers (drive circuits) to drive the switches, a control circuit to control the drivers, etc. In each of the high side switch and the low side switch, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used. Here, a high side switch is also called a control switch and a low side switch is also called a synchronous switch.
In a semiconductor device used for a power supply circuit such as a DC/DC converter, for example the following technologies are proposed with the aim of downsizing and reducing the inductance of a wire.
(1) Japanese Unexamined Patent Publication No. 2005-203584 (Patent Literature 1)
A power MOSFET for a high side switch, a drive circuit to drive the power MOSFET for the high side switch, and a drive circuit to drive a power MOSFET for a low side switch are formed in one semiconductor chip. A power MOSFET for the low side switch is formed in another chip. The two semiconductor chips are contained in one package.
(2) Japanese Unexamined Patent Publication No. 2010-16035 (Patent Literature 2)
A power MOSFET for a high side switch, a power MOSFET for a low side switch, and drivers and control circuits for them are formed over one semiconductor substrate.